View Single Post
Old 04-10-2018, 04:06 PM   #22 (permalink)
cr45
EcoModding Apprentice
 
Join Date: Oct 2010
Location: ireland
Posts: 102
Thanks: 8
Thanked 52 Times in 34 Posts
Quote:
Originally Posted by RedDevil View Post
Inertia is not linear but quadratic to speed.
It takes 0.5 Joule to speed up that kilogram to 1 meter per second, it takes 2 Joule for 2 m/s, 4.5 for 3 m/s, etc.
Inertia, if you mean the contained energy, in your formula is not mass * radius but mass * (radius ^ 2) / 2.

And remember, only the speed matters, not the direction; whether it is straight, turning slowly in a big circle or fast in a tiny circle is indifferent. Only its speed matters.
You appear to be confusing the term "inertia" with "kinetic energy".

A mass M moving at a velocity V has a kinetic energy of 0.5 * M * V * V.

This however is not inertia.

Inertia is a measure of a body's resistance to changes in velocity.

It can be found from Newton's second law F = M * A and thus M = F / A

As there is no gravity in space, astronauts determine their mass (inertia) in a special device that applies a force and the rate of acceleration is measured. The rearranged Newtons 2nd equation is then used to calculate their mass (inertia).
  Reply With Quote
The Following User Says Thank You to cr45 For This Useful Post:
RedDevil (04-10-2018)